Publications by authors named "Pak C Sham"

198 Publications

Integrative analysis of metabolomic, genomic, and imaging-based phenotypes identify very-low-density lipoprotein as a potential risk factor for lumbar Modic changes.

Eur Spine J 2021 Sep 25. Epub 2021 Sep 25.

Department of Orthopaedics and Traumatology, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.

Purpose: Modic changes (MC) on magnetic resonance imaging (MRI) have been associated with the development and severity of low back pain (LBP). The etiology of MC remains elusive, but it has been suggested that altered metabolism may be a risk factor. As such, this study aimed to identify metabolomic biomarkers for MC phenotypes of the lumbar spine via a combined metabolomic-genomic approach.

Methods: A population cohort of 3,584 southern Chinese underwent lumbar spine MRI. Blood samples were genotyped with single-nucleotide polymorphisms (SNP) arrays (n = 2,482) and serum metabolomics profiling using magnetic resonance spectroscopy (n = 757), covering 130 metabolites representing three molecular windows, were assessed. Genome-wide association studies (GWAS) were performed on each metabolite, to construct polygenic scores for predicting metabolite levels in subjects who had GWAS but not metabolomic data. Associations between predicted metabolite levels and MC phenotypes were assessed using linear/logistic regression and least absolute shrinkage and selection operator (LASSO). Two-sample Mendelian randomization analysis tested for causal relationships between metabolic biomarkers and MC.

Results: 20.4% had MC (10.6% type 1, 67.2% type 2, 22.2% mixed types). Significant MC metabolomic biomarkers were mean diameter of very-low-density lipoprotein (VLDL)/low-density lipoprotein (LDL) particles and cholesterol esters/phospholipids in large LDL. Mendelian randomization indicated that decreased VLDL mean diameter may lead to MC.

Conclusions: This large-scale study is the first to address metabolomics in subject with/without lumbar MC. Causality studies implicate VLDL related to MC, noting a metabolic etiology. Our study substantiates the field of "spino-metabolomics" and illustrates the power of integrating metabolomics-genomics-imaging phenotypes to discover biomarkers for spinal disorders, paving the way for more personalized spine care for patients.
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http://dx.doi.org/10.1007/s00586-021-06995-xDOI Listing
September 2021

The continuity of effect of schizophrenia polygenic risk score and patterns of cannabis use on transdiagnostic symptom dimensions at first-episode psychosis: findings from the EU-GEI study.

Transl Psychiatry 2021 08 10;11(1):423. Epub 2021 Aug 10.

Department of Psychiatry, Early Psychosis Section, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands.

Diagnostic categories do not completely reflect the heterogeneous expression of psychosis. Using data from the EU-GEI study, we evaluated the impact of schizophrenia polygenic risk score (SZ-PRS) and patterns of cannabis use on the transdiagnostic expression of psychosis. We analysed first-episode psychosis patients (FEP) and controls, generating transdiagnostic dimensions of psychotic symptoms and experiences using item response bi-factor modelling. Linear regression was used to test the associations between these dimensions and SZ-PRS, as well as the combined effect of SZ-PRS and cannabis use on the dimensions of positive psychotic symptoms and experiences. We found associations between SZ-PRS and (1) both negative (B = 0.18; 95%CI 0.03-0.33) and positive (B = 0.19; 95%CI 0.03-0.35) symptom dimensions in 617 FEP patients, regardless of their categorical diagnosis; and (2) all the psychotic experience dimensions in 979 controls. We did not observe associations between SZ-PRS and the general and affective dimensions in FEP. Daily and current cannabis use were associated with the positive dimensions in FEP (B = 0.31; 95%CI 0.11-0.52) and in controls (B = 0.26; 95%CI 0.06-0.46), over and above SZ-PRS. We provide evidence that genetic liability to schizophrenia and cannabis use map onto transdiagnostic symptom dimensions, supporting the validity and utility of the dimensional representation of psychosis. In our sample, genetic liability to schizophrenia correlated with more severe psychosis presentation, and cannabis use conferred risk to positive symptomatology beyond the genetic risk. Our findings support the hypothesis that psychotic experiences in the general population have similar genetic substrates as clinical disorders.
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http://dx.doi.org/10.1038/s41398-021-01526-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8355107PMC
August 2021

Sex-Dependent Shared and Nonshared Genetic Architecture Across Mood and Psychotic Disorders.

Biol Psychiatry 2021 Mar 23. Epub 2021 Mar 23.

Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, Illinois; Department of Psychiatry and Behavioral Sciences, North Shore University Health System, Evanston, Illinois.

Background: Sex differences in incidence and/or presentation of schizophrenia (SCZ), major depressive disorder (MDD), and bipolar disorder (BIP) are pervasive. Previous evidence for shared genetic risk and sex differences in brain abnormalities across disorders suggest possible shared sex-dependent genetic risk.

Methods: We conducted the largest to date genome-wide genotype-by-sex (G×S) interaction of risk for these disorders using 85,735 cases (33,403 SCZ, 19,924 BIP, and 32,408 MDD) and 109,946 controls from the PGC (Psychiatric Genomics Consortium) and iPSYCH.

Results: Across disorders, genome-wide significant single nucleotide polymorphism-by-sex interaction was detected for a locus encompassing NKAIN2 (rs117780815, p = 3.2 × 10), which interacts with sodium/potassium-transporting ATPase (adenosine triphosphatase) enzymes, implicating neuronal excitability. Three additional loci showed evidence (p < 1 × 10) for cross-disorder G×S interaction (rs7302529, p = 1.6 × 10; rs73033497, p = 8.8 × 10; rs7914279, p = 6.4 × 10), implicating various functions. Gene-based analyses identified G×S interaction across disorders (p = 8.97 × 10) with transcriptional inhibitor SLTM. Most significant in SCZ was a MOCOS gene locus (rs11665282, p = 1.5 × 10), implicating vascular endothelial cells. Secondary analysis of the PGC-SCZ dataset detected an interaction (rs13265509, p = 1.1 × 10) in a locus containing IDO2, a kynurenine pathway enzyme with immunoregulatory functions implicated in SCZ, BIP, and MDD. Pathway enrichment analysis detected significant G×S interaction of genes regulating vascular endothelial growth factor receptor signaling in MDD (false discovery rate-corrected p < .05).

Conclusions: In the largest genome-wide G×S analysis of mood and psychotic disorders to date, there was substantial genetic overlap between the sexes. However, significant sex-dependent effects were enriched for genes related to neuronal development and immune and vascular functions across and within SCZ, BIP, and MDD at the variant, gene, and pathway levels.
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http://dx.doi.org/10.1016/j.biopsych.2021.02.972DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8458480PMC
March 2021

The effects of maternal SSRI exposure on the serotonin system, prefrontal protein expression and behavioral development in male and female offspring rats.

Neurochem Int 2021 06 6;146:105041. Epub 2021 Apr 6.

School of Rehabilitation, Kunming Medical University, Kunming, China. Electronic address:

Fluoxetine (FLX), a commonly used selective serotonin reuptake inhibitor, is often used to treat depression during pregnancy. However, prenatal exposure to FLX has been associated with a series of neuropsychiatric illnesses. The use of a rodent model can provide a clear indication as to whether prenatal exposure to SSRIs, independent of maternal psychiatric disorders or genetic syndromes, can cause long-term behavioral abnormalities in offspring. Thus, the present study aimed to explore whether prenatal FLX exposure causes long-term neurobehavioral effects, and identify the underlying mechanism between FLX and abnormal behaviors. In our study, 12/mg/kg/day of FLX or equal normal saline (NS) was administered to pregnant Sprague-Dawley (SD) rats (FLX = 30, NS = 27) on gestation day 11 till birth. We assessed the physical development and behavior of offspring, and in vivo magnetic resonance spectroscopy (MRS) was conducted to quantify biochemical alterations in the prefrontal cortex (PFC). Ex vivo measurements of brain serotonin level and a proteomic analysis were also undertaken. Our results showed that the offspring (male offspring in particular) of fluoxetine exposed mothers showed delayed physical development, increased anxiety-like behavior, and impaired social interaction. Moreover, down-regulation of 5-HT and SERT expression were identified in the PFC. We also found that prenatal FLX exposure significantly decreased NAA/tCr with 1H-MRS in the PFC of offspring. Finally, a proteomic study revealed sex-dependent differential protein expression. These findings may have translational importance suggesting that using SSRI medication alone in pregnant mothers may result in developmental delay in their offspring. Our results also help guide the choice of outcome measures in identifying of molecular and developmental mechanisms.
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http://dx.doi.org/10.1016/j.neuint.2021.105041DOI Listing
June 2021

Valproate Reverses Mania-Like Behavior of Mouse and Alters Monoamine Neurotransmitters Metabolism in the Hippocampus.

Neuropsychiatr Dis Treat 2021 11;17:471-480. Epub 2021 Feb 11.

Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, People's Republic of China.

Background: Mice with a deletion at exon 19 of the circadian locomotor output cycles Kaput gene ( ) exhibit mania-like behavior and have been one of the most common animal models for bipolar disorder (BD). The predictive validity of the was investigated via studies using lithium previously. Determination of effects of other mood stabilizers on mouse would be helpful for better understanding of the mechanism underlined.

Methods: Wildtype (WT) and mice were treated with saline (n = 10 for WT and n=10 for ) or valproate (VPA) (n = 10 for WT and n=10 for ) for 10 days. The hyperactivity, anxiety-like behaviors and depression-like behaviors were tested. The concentration of monoamine neurotransmitters and their metabolites in the hippocampus of saline or VPA treated WT and mouse (n = 8 for each) were also determined.

Results: VPA can reverse hyperactivity, lower level of anxiety-like and depression-like behaviors of the mouse. mouse exhibited lower levels of serotonin (5-HT) and dopamine (DA) in right hippocampus compared to WT mouse. Chronic VPA treatment did not affect the levels of 5-HT and DA, but can reduce the level of levodopa (L-DOPA) in the right hippocampus of mouse.

Conclusion: Our results indicated that chronic VPA treatment can reverse the mania-like behaviors of the mouse and further consolidate the validity of the mouse as a model of BD. Monoamine neurotransmitters and their metabolites in the hippocampus are partly regulated by mutation of the gene or VPA treatment.
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http://dx.doi.org/10.2147/NDT.S293482DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7884953PMC
February 2021

Identification of 38 novel loci for systemic lupus erythematosus and genetic heterogeneity between ancestral groups.

Nat Commun 2021 02 3;12(1):772. Epub 2021 Feb 3.

Department of Medicine, The University of Hong Kong, Hong Kong, China.

Systemic lupus erythematosus (SLE), a worldwide autoimmune disease with high heritability, shows differences in prevalence, severity and age of onset among different ancestral groups. Previous genetic studies have focused more on European populations, which appear to be the least affected. Consequently, the genetic variations that underlie the commonalities, differences and treatment options in SLE among ancestral groups have not been well elucidated. To address this, we undertake a genome-wide association study, increasing the sample size of Chinese populations to the level of existing European studies. Thirty-eight novel SLE-associated loci and incomplete sharing of genetic architecture are identified. In addition to the human leukocyte antigen (HLA) region, nine disease loci show clear ancestral differences and implicate antibody production as a potential mechanism for differences in disease manifestation. Polygenic risk scores perform significantly better when trained on ancestry-matched data sets. These analyses help to reveal the genetic basis for disparities in SLE among ancestral groups.
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http://dx.doi.org/10.1038/s41467-021-21049-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7858632PMC
February 2021

Neurological Soft Signs Are Associated With Altered Cerebellar-Cerebral Functional Connectivity in Schizophrenia.

Schizophr Bull 2021 08;47(5):1452-1462

Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China.

Cerebellar dysfunction is associated with neurological soft signs (NSS), which is a promising endophenotype for schizophrenia spectrum disorders. However, the relationship between cerebellar-cerebral resting-state functional connectivity (rsFC) and NSS is largely unexplored. Moreover, both NSS and cerebellar-cerebral rsFC have been found to be correlated with negative symptoms of schizophrenia. Here, we investigated the correlations between NSS and cerebellar-cerebral rsFC, explored their relationship with negative symptoms in a main dataset, and validated the significant findings in a replication dataset. Both datasets comprised schizophrenia patients and healthy controls. In schizophrenia patients, we found positive correlations between NSS and rsFC of the cerebellum with the inferior frontal gyrus and the precuneus, and negative correlations between NSS and rsFC of the cerebellum with the inferior temporal gyrus. In healthy controls, NSS scores were positively correlated with rsFC of the cerebellum with the superior frontal gyrus and negatively correlated with rsFC between the cerebellum and the middle occipital gyrus. Cerebellar-prefrontal rsFC was also positively correlated with negative symptoms in schizophrenia patients. These findings were validated in the replication dataset. Our results suggest that the uncoupling of rsFC between the cerebellum and the cerebral cortex may underlie the expression of NSS in schizophrenia. NSS-related cerebellar-prefrontal rsFC may be a potential neural pathway for possible neural modulation to alleviate negative symptoms.
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http://dx.doi.org/10.1093/schbul/sbaa200DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8379549PMC
August 2021

Modeling Parent-Specific Genetic Nurture in Families with Missing Parental Genotypes: Application to Birthweight and BMI.

Behav Genet 2021 05 16;51(3):289-300. Epub 2021 Jan 16.

Department of Psychiatry, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China.

Disaggregation and estimation of genetic effects from offspring and parents has long been of interest to statistical geneticists. Recently, technical and methodological advances have made the genome-wide and loci-specific estimation of direct offspring and parental genetic nurture effects more possible. However, unbiased estimation using these methods requires datasets where both parents and at least one child have been genotyped, which are relatively scarce. Our group has recently developed a method and accompanying software (IMPISH; Hwang et al. in PLoS Genet 16:e1009154, 2020) which is able to impute missing parental genotypes from observed data on sibships and estimate their effects on an offspring phenotype conditional on the effects of genetic transmission. However, this method is unable to disentangle maternal and paternal effects, which may differ in magnitude and direction. Here, we introduce an extension to the original IMPISH routine which takes advantage of all available nuclear families to impute parent-specific missing genotypes and obtain asymptotically unbiased estimates of genetic effects on offspring phenotypes. We apply this this method to data from related individuals in the UK Biobank, showing concordance with previous estimates of maternal genetic effects on offspring birthweight. We also conduct the first GWAS jointly estimating offspring-, maternal-, and paternal-specific genetic effects on body-mass index.
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http://dx.doi.org/10.1007/s10519-020-10040-wDOI Listing
May 2021

DIPPER, a spatiotemporal proteomics atlas of human intervertebral discs for exploring ageing and degeneration dynamics.

Elife 2020 12 31;9. Epub 2020 Dec 31.

School of Biomedical Sciences,, The University of Hong Kong, Hong Kong.

The spatiotemporal proteome of the intervertebral disc (IVD) underpins its integrity and function. We present DIPPER, a deep and comprehensive IVD proteomic resource comprising 94 genome-wide profiles from 17 individuals. To begin with, protein modules defining key directional trends spanning the lateral and anteroposterior axes were derived from high-resolution spatial proteomes of intact young cadaveric lumbar IVDs. They revealed novel region-specific profiles of regulatory activities and displayed potential paths of deconstruction in the level- and location-matched aged cadaveric discs. Machine learning methods predicted a 'hydration matrisome' that connects extracellular matrix with MRI intensity. Importantly, the static proteome used as point-references can be integrated with dynamic proteome (SILAC/degradome) and transcriptome data from multiple clinical samples, enhancing robustness and clinical relevance. The data, findings, and methodology, available on a web interface (http://www.sbms.hku.hk/dclab/DIPPER/), will be valuable references in the field of IVD biology and proteomic analytics.
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http://dx.doi.org/10.7554/eLife.64940DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7857729PMC
December 2020

Estimating indirect parental genetic effects on offspring phenotypes using virtual parental genotypes derived from sibling and half sibling pairs.

PLoS Genet 2020 10 26;16(10):e1009154. Epub 2020 Oct 26.

The University of Queensland Diamantina Institute, The University of Queensland, Brisbane, Australia.

Indirect parental genetic effects may be defined as the influence of parental genotypes on offspring phenotypes over and above that which results from the transmission of genes from parents to their children. However, given the relative paucity of large-scale family-based cohorts around the world, it is difficult to demonstrate parental genetic effects on human traits, particularly at individual loci. In this manuscript, we illustrate how parental genetic effects on offspring phenotypes, including late onset conditions, can be estimated at individual loci in principle using large-scale genome-wide association study (GWAS) data, even in the absence of parental genotypes. Our strategy involves creating "virtual" mothers and fathers by estimating the genotypic dosages of parental genotypes using physically genotyped data from relative pairs. We then utilize the expected dosages of the parents, and the actual genotypes of the offspring relative pairs, to perform conditional genetic association analyses to obtain asymptotically unbiased estimates of maternal, paternal and offspring genetic effects. We apply our approach to 19066 sibling pairs from the UK Biobank and show that a polygenic score consisting of imputed parental educational attainment SNP dosages is strongly related to offspring educational attainment even after correcting for offspring genotype at the same loci. We develop a freely available web application that quantifies the power of our approach using closed form asymptotic solutions. We implement our methods in a user-friendly software package IMPISH (IMputing Parental genotypes In Siblings and Half Siblings) which allows users to quickly and efficiently impute parental genotypes across the genome in large genome-wide datasets, and then use these estimated dosages in downstream linear mixed model association analyses. We conclude that imputing parental genotypes from relative pairs may provide a useful adjunct to existing large-scale genetic studies of parents and their offspring.
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http://dx.doi.org/10.1371/journal.pgen.1009154DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7646364PMC
October 2020

Cerebellar hypoactivation is associated with impaired sensory integration in schizophrenia.

J Abnorm Psychol 2021 Jan 19;130(1):102-111. Epub 2020 Oct 19.

Neuropsychology and Applied Cognitive Neuroscience Laboratory.

To clarify the involvement of the cerebellum in impaired sensory integration in patients with schizophrenia, 52 first-episode patients with schizophrenia and 52 age- and sex-matched healthy controls underwent a verified sensory integration imaging task to examine the whole-brain dysfunction underlying impaired sensory integration. The familiality of cerebellar activation when integrating sensory stimuli was investigated in 25 siblings of the patients with schizophrenia, while the heritability of cerebellar activation was estimated in 56 monozygotic twins and 56 dizygotic twins. In addition, the functional connectivity between the cerebellum and the remaining regions of the whole brain was explored with psychophysiological interaction analysis. Relative to healthy controls, patients with schizophrenia showed reduced cerebellar activation when performing the sensory integration task in the whole-brain analysis. This reduced cerebellar activation was also found in the siblings of patients with schizophrenia, but to a lesser extent compared with schizophrenia patients. Cerebellar activation during sensory integration was also found to be significantly heritable. Furthermore, dysconnectivity within the cerebellum was found in patients with schizophrenia when integrating auditory and visual stimuli. These findings highlight the role of cerebellar dysfunction in the pathophysiology of schizophrenia symptoms and its potential role as an endophenotype of schizophrenia spectrum disorders. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
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http://dx.doi.org/10.1037/abn0000636DOI Listing
January 2021

Systemic neuro-dysregulation in depression: Evidence from genome-wide association.

Eur Neuropsychopharmacol 2020 10 4;39:1-18. Epub 2020 Sep 4.

Department of Psychiatry, The University of Hong Kong, Hong Kong; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong; Centre of PanorOmic Sciences, The University of Hong Kong, Hong Kong. Electronic address:

Depression is the world's leading cause of disability. Greater understanding of the neurobiological basis of depression is necessary for developing novel treatments with improved efficacy and acceptance. Recently, major advances have been made in the search for genetic variants associated with depression which may help to elucidate etiological mechanisms. The present review has two major objectives. First, we offer a brief review of two major biological systems with strong evidence for involvement in depression pathology: neurotransmitter systems and the stress response. Secondly, we provide a synthesis of the functions of the 269 genes implicated by the most recent genome-wide meta-analysis, supporting the importance of these systems in depression and providing insights into other possible mechanisms involving neurodevelopment, neurogenesis, and neurodegeneration. Our goal is to undertake a broad, preliminary stock-taking of the most recent hypothesis-free findings and examine the weight of the evidence supporting these existing theories and highlighting novel directions. This qualitative review and accompanying gene function table provides a valuable resource and guide for basic and translational researchers, with suggestions for future mechanistic research, leveraging genetics to prioritize studies on the neurobiological processes involved in depression etiology and treatment.
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http://dx.doi.org/10.1016/j.euroneuro.2020.08.007DOI Listing
October 2020

The Genes We Inherit and Those We Don't: Maternal Genetic Nurture and Child BMI Trajectories.

Behav Genet 2020 09 17;50(5):310-319. Epub 2020 Jul 17.

Department of Psychiatry, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong SAR, China.

Recently, methods have been introduced using polygenic scores (PGS) to estimate the effects of genetic nurture, the environmentally-mediated effects of parental genotypes on the phenotype of their child above and beyond the effects of the alleles which are transmitted to the child. We introduce a simplified model for estimating genetic nurture effects and show, through simulation and analytical derivation, that our method provides unbiased estimates and offers an increase in power to detect genetic nurture of up to 1/3 greater than that of previous methods. Subsequently, we apply this method to data from the Avon Longitudinal Study of Parents and Children to estimate the effects of maternal genetic nurture on childhood body mass index (BMI) trajectories. Through mixed modeling, we observe a statistically significant age-dependent effect of maternal PGS on child BMI, such that the influence of maternal genetic nurture appears to increase throughout development.
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http://dx.doi.org/10.1007/s10519-020-10008-wDOI Listing
September 2020

Immune dysregulation in depression: Evidence from genome-wide association.

Brain Behav Immun Health 2020 Aug 17;7:100108. Epub 2020 Jul 17.

Department of Psychiatry, The University of Hong Kong, Hong Kong.

A strong body of evidence supports a role for immune dysregulation across many psychiatric disorders including depression, the leading cause of global disability. Recent progress in the search for genetic variants associated with depression provides the opportunity to strengthen our current understanding of etiological factors contributing to depression and generate novel hypotheses. Here, we provide an overview of the literature demonstrating a role for immune dysregulation in depression, followed by a detailed discussion of the immune-related genes identified by the most recent genome-wide meta-analysis of depression. These genes represent strong evidence-based targets for future basic and translational research which aims to understand the role of the immune system in depression pathology and identify novel points for therapeutic intervention.
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http://dx.doi.org/10.1016/j.bbih.2020.100108DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8474691PMC
August 2020

Statistical Power and the Classical Twin Design.

Twin Res Hum Genet 2020 04;23(2):87-89

Analytic and Translational Genetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA.

Dr Nick Martin has made enormous contributions to the field of behavior genetics over the past 50 years. Of his many seminal papers that have had a profound impact, we focus on his early work on the power of twin studies. He was among the first to recognize the importance of sample size calculation before conducting a study to ensure sufficient power to detect the effects of interest. The elegant approach he developed, based on the noncentral chi-squared distribution, has been adopted by subsequent researchers for other genetic study designs, and today remains a standard tool for power calculations in structural equation modeling and other areas of statistical analysis. The present brief article discusses the main aspects of his seminal paper, and how it led to subsequent developments, by him and others, as the field of behavior genetics evolved into the present era.
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http://dx.doi.org/10.1017/thg.2020.46DOI Listing
April 2020

Knowledge-based analyses reveal new candidate genes associated with risk of hepatitis B virus related hepatocellular carcinoma.

BMC Cancer 2020 May 11;20(1):403. Epub 2020 May 11.

Department of Psychiatry, the University of Hong Kong, Pokfulam, Hong Kong.

Background: Recent genome-wide association studies (GWASs) have suggested several susceptibility loci of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) by statistical analysis at individual single-nucleotide polymorphisms (SNPs). However, these loci only explain a small fraction of HBV-related HCC heritability. In the present study, we aimed to identify additional susceptibility loci of HBV-related HCC using advanced knowledge-based analysis.

Methods: We performed knowledge-based analysis (including gene- and gene-set-based association tests) on variant-level association p-values from two existing GWASs of HBV-related HCC. Five different types of gene-sets were collected for the association analysis. A number of SNPs within the gene prioritized by the knowledge-based association tests were selected to replicate genetic associations in an independent sample of 965 cases and 923 controls.

Results: The gene-based association analysis detected four genes significantly or suggestively associated with HBV-related HCC risk: SLC39A8, GOLGA8M, SMIM31, and WHAMMP2. The gene-set-based association analysis prioritized two promising gene sets for HCC, cell cycle G1/S transition and NOTCH1 intracellular domain regulates transcription. Within the gene sets, three promising candidate genes (CDC45, NCOR1 and KAT2A) were further prioritized for HCC. Among genes of liver-specific expression, multiple genes previously implicated in HCC were also highlighted. However, probably due to small sample size, none of the genes prioritized by the knowledge-based association analyses were successfully replicated by variant-level association test in the independent sample.

Conclusions: This comprehensive knowledge-based association mining study suggested several promising genes and gene-sets associated with HBV-related HCC risks, which would facilitate follow-up functional studies on the pathogenic mechanism of HCC.
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http://dx.doi.org/10.1186/s12885-020-06842-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7216662PMC
May 2020

Knowledge-based analyses reveal new candidate genes associated with risk of hepatitis B virus related hepatocellular carcinoma.

BMC Cancer 2020 May 11;20(1):403. Epub 2020 May 11.

Department of Psychiatry, the University of Hong Kong, Pokfulam, Hong Kong.

Background: Recent genome-wide association studies (GWASs) have suggested several susceptibility loci of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) by statistical analysis at individual single-nucleotide polymorphisms (SNPs). However, these loci only explain a small fraction of HBV-related HCC heritability. In the present study, we aimed to identify additional susceptibility loci of HBV-related HCC using advanced knowledge-based analysis.

Methods: We performed knowledge-based analysis (including gene- and gene-set-based association tests) on variant-level association p-values from two existing GWASs of HBV-related HCC. Five different types of gene-sets were collected for the association analysis. A number of SNPs within the gene prioritized by the knowledge-based association tests were selected to replicate genetic associations in an independent sample of 965 cases and 923 controls.

Results: The gene-based association analysis detected four genes significantly or suggestively associated with HBV-related HCC risk: SLC39A8, GOLGA8M, SMIM31, and WHAMMP2. The gene-set-based association analysis prioritized two promising gene sets for HCC, cell cycle G1/S transition and NOTCH1 intracellular domain regulates transcription. Within the gene sets, three promising candidate genes (CDC45, NCOR1 and KAT2A) were further prioritized for HCC. Among genes of liver-specific expression, multiple genes previously implicated in HCC were also highlighted. However, probably due to small sample size, none of the genes prioritized by the knowledge-based association analyses were successfully replicated by variant-level association test in the independent sample.

Conclusions: This comprehensive knowledge-based association mining study suggested several promising genes and gene-sets associated with HBV-related HCC risks, which would facilitate follow-up functional studies on the pathogenic mechanism of HCC.
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http://dx.doi.org/10.1186/s12885-020-06842-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7216662PMC
May 2020

Jumping to conclusions, general intelligence, and psychosis liability: findings from the multi-centre EU-GEI case-control study.

Psychol Med 2021 03 24;51(4):623-633. Epub 2020 Apr 24.

Section of Psychiatry, Azienda Ospedaliera Universitaria Integrata di Verona, Verona, Italy.

Background: The 'jumping to conclusions' (JTC) bias is associated with both psychosis and general cognition but their relationship is unclear. In this study, we set out to clarify the relationship between the JTC bias, IQ, psychosis and polygenic liability to schizophrenia and IQ.

Methods: A total of 817 first episode psychosis patients and 1294 population-based controls completed assessments of general intelligence (IQ), and JTC, and provided blood or saliva samples from which we extracted DNA and computed polygenic risk scores for IQ and schizophrenia.

Results: The estimated proportion of the total effect of case/control differences on JTC mediated by IQ was 79%. Schizophrenia polygenic risk score was non-significantly associated with a higher number of beads drawn (B = 0.47, 95% CI -0.21 to 1.16, p = 0.17); whereas IQ PRS (B = 0.51, 95% CI 0.25-0.76, p < 0.001) significantly predicted the number of beads drawn, and was thus associated with reduced JTC bias. The JTC was more strongly associated with the higher level of psychotic-like experiences (PLEs) in controls, including after controlling for IQ (B = -1.7, 95% CI -2.8 to -0.5, p = 0.006), but did not relate to delusions in patients.

Conclusions: Our findings suggest that the JTC reasoning bias in psychosis might not be a specific cognitive deficit but rather a manifestation or consequence, of general cognitive impairment. Whereas, in the general population, the JTC bias is related to PLEs, independent of IQ. The work has the potential to inform interventions targeting cognitive biases in early psychosis.
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http://dx.doi.org/10.1017/S003329171900357XDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8020493PMC
March 2021

Intermediate confounding in trio relationships: The importance of complete data in effect size estimation.

Genet Epidemiol 2020 06 27;44(4):395-399. Epub 2020 Mar 27.

Department of Psychiatry, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong SAR, China.

We present an important characteristic of trio models which may lead to bias and loss of power when one parent is unmodeled in trio analyses. Motivated by recent interest in estimating parental effects on postnatal and later-life phenotypes, we consider a causal model where each parent has both an effect on their child's phenotype which is mediated through the genotype transmitted to the child and a direct effect on the phenotype through the parentally provided environment. We derive the power and bias of models in which one parent's genotype is not modeled, showing that while the effect of the child's genotype is biased in the direction of the unmodeled parent's effect as expected, the estimated effect of the observed parent's genotype is also biased in the opposite direction. While this phenomenon may not be intuitive under the assumption of random mating, it can be explained by intermediate confounding of the child's genotype-phenotype effect. These observations have implications for the accurate estimation of maternal and paternal effects in trio data sets with missing genotype data.
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http://dx.doi.org/10.1002/gepi.22294DOI Listing
June 2020

Interleukin-18 levels in the hippocampus and behavior of adult rat offspring exposed to prenatal restraint stress during early and late pregnancy.

Neural Regen Res 2020 Sep;15(9):1748-1756

Department of Psychiatry; State Key Laboratory of Brain and Cognitive Sciences; Centre for Genomic Sciences, The University of Hong Kong, Hong Kong Special Administrative Region, China.

Exposure to maternal stress during prenatal life is associated with an increased risk of neuropsychiatric disorders, such as depression and anxiety, in offspring. It has also been increasingly observed that prenatal stress alters the phenotype of offspring via immunological mechanisms and that immunological dysfunction, such as elevated interleukin-18 levels, has been reported in cultures of microglia. Prenatal restraint stress (PRS) in rats permits direct experimental investigation of the link between prenatal stress and adverse outcomes. However, the majority of studies have focused on the consequences of PRS delivered in the second half of pregnancy, while the effects of early prenatal stress have rarely been examined. Therefore, pregnant rats were subjected to PRS during early/middle and late gestation (days 8-14 and 15-21, respectively). PRS comprised restraint in a round plastic transparent cylinder under bright light (6500 lx) three times per day for 45 minutes. Differences in interleukin-18 expression in the hippocampus and in behavior were compared between offspring rats and control rats on postnatal day 75. We found that adult male offspring exposed to PRS during their late prenatal periods had higher levels of anxiety-related behavior and depression than control rats, and both male and female offspring exhibited higher levels of depression-related behavior, impaired recognition memory and diminished exploration of novel objects. Moreover, an elevated level of interleukin-18 was observed in the dorsal and ventral hippocampus of male and female early- and late-PRS offspring rats. The results indicate that PRS can cause anxiety and depression-related behaviors in adult offspring and affect the expression of interleukin-18 in the hippocampus. Thus, behavior and the molecular biology of the brain are affected by the timing of PRS exposure and the sex of the offspring. All experiments were approved by the Animal Experimentation Ethics Committee at Kunming Medical University, China (approval No. KMMU2019074) in January 2019.
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http://dx.doi.org/10.4103/1673-5374.276358DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7437598PMC
September 2020

Daily use of high-potency cannabis is associated with more positive symptoms in first-episode psychosis patients: the EU-GEI case-control study.

Psychol Med 2020 Mar 18:1-9. Epub 2020 Mar 18.

Department of Psychiatry, Early Psychosis Section, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.

Background: Daily use of high-potency cannabis has been reported to carry a high risk for developing a psychotic disorder. However, the evidence is mixed on whether any pattern of cannabis use is associated with a particular symptomatology in first-episode psychosis (FEP) patients.

Method: We analysed data from 901 FEP patients and 1235 controls recruited across six countries, as part of the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study. We used item response modelling to estimate two bifactor models, which included general and specific dimensions of psychotic symptoms in patients and psychotic experiences in controls. The associations between these dimensions and cannabis use were evaluated using linear mixed-effects models analyses.

Results: In patients, there was a linear relationship between the positive symptom dimension and the extent of lifetime exposure to cannabis, with daily users of high-potency cannabis having the highest score (B = 0.35; 95% CI 0.14-0.56). Moreover, negative symptoms were more common among patients who never used cannabis compared with those with any pattern of use (B = -0.22; 95% CI -0.37 to -0.07). In controls, psychotic experiences were associated with current use of cannabis but not with the extent of lifetime use. Neither patients nor controls presented differences in depressive dimension related to cannabis use.

Conclusions: Our findings provide the first large-scale evidence that FEP patients with a history of daily use of high-potency cannabis present with more positive and less negative symptoms, compared with those who never used cannabis or used low-potency types.
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http://dx.doi.org/10.1017/S0033291720000082DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8223239PMC
March 2020

MTMR4 SNVs modulate ion channel degradation and clinical severity in congenital long QT syndrome: insights in the mechanism of action of protective modifier genes.

Cardiovasc Res 2021 02;117(3):767-779

Laboratory of Experimental Cardiology for Cell and Molecular Therapy, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.

Aims: In long QT syndrome (LQTS) patients, modifier genes modulate the arrhythmic risk associated with a disease-causing mutation. Their recognition can improve risk stratification and clinical management, but their discovery represents a challenge. We tested whether a cellular-driven approach could help to identify new modifier genes and especially their mechanism of action.

Methods And Results: We generated human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM) from two patients carrying the same KCNQ1-Y111C mutation, but presenting opposite clinical phenotypes. We showed that the phenotype of the iPSC-CMs derived from the symptomatic patient is due to impaired trafficking and increased degradation of the mutant KCNQ1 and wild-type human ether-a-go-go-related gene. In the iPSC-CMs of the asymptomatic (AS) patient, the activity of an E3 ubiquitin-protein ligase (Nedd4L) involved in channel protein degradation was reduced and resulted in a decreased arrhythmogenic substrate. Two single-nucleotide variants (SNVs) on the Myotubularin-related protein 4 (MTMR4) gene, an interactor of Nedd4L, were identified by whole-exome sequencing as potential contributors to decreased Nedd4L activity. Correction of these SNVs by CRISPR/Cas9 unmasked the LQTS phenotype in AS cells. Importantly, the same MTMR4 variants were present in 77% of AS Y111C mutation carriers of a separate cohort. Thus, genetically mediated interference with Nedd4L activation seems associated with protective effects.

Conclusion: Our finding represents the first demonstration of the cellular mechanism of action of a protective modifier gene in LQTS. It provides new clues for advanced risk stratification and paves the way for the design of new therapies targeting this specific molecular pathway.
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http://dx.doi.org/10.1093/cvr/cvaa019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7898949PMC
February 2021

Directed Differentiation of Notochord-like and Nucleus Pulposus-like Cells Using Human Pluripotent Stem Cells.

Cell Rep 2020 02;30(8):2791-2806.e5

Department of Medicine, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong; Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, Guangdong 510080, China; The State Key Laboratory of Pharmaceutical Biotechnology, the University of Hong Kong, Hong Kong. Electronic address:

Intervertebral disc degeneration might be amenable to stem cell therapy, but the required cells are scarce. Here, we report the development of a protocol for directed in vitro differentiation of human pluripotent stem cells (hPSCs) into notochord-like and nucleus pulposus (NP)-like cells of the disc. The first step combines enhancement of ACTIVIN/NODAL and WNT and inhibition of BMP pathways. By day 5 of differentiation, hPSC-derived cells express notochordal cell characteristic genes. After activating the TGF-β pathway for an additional 15 days, qPCR, immunostaining, and transcriptome data show that a wide array of NP markers are expressed. Transcriptomically, the in vitro-derived cells become more like in vivo adolescent human NP cells, driven by a set of influential genes enriched with motifs bound by BRACHYURY and FOXA2, consistent with an NP cell-like identity. Transplantation of these NP-like cells attenuates fibrotic changes in a rat disc injury model of disc degeneration.
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http://dx.doi.org/10.1016/j.celrep.2020.01.100DOI Listing
February 2020

Inheritance of Neural Substrates for Motivation and Pleasure.

Psychol Sci 2019 08 18;30(8):1205-1217. Epub 2019 Jul 18.

1 Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences.

Despite advances in the understanding of the reward system and the role of dopamine in recent decades, the heritability of the underlying neural mechanisms is not known. In the present study, we examined the hemodynamic activation of the nucleus accumbens (NAcc), a key hub of the reward system, in 86 healthy monozygotic twins and 88 healthy dizygotic twins during a monetary-incentive-delay task. The participants also completed self-report measures of pleasure. Using voxelwise heritability mapping, we found that activation of the bilateral NAcc during the anticipation of monetary gains had significant heritability ( = .20-.49). Moreover, significant shared genetic covariance was observed between pleasure and NAcc activation during the anticipation of monetary gain. These findings suggest that both NAcc activation and self-reported pleasure may be heritable and that their phenotypic correlation may be partially explained by shared genetic variation.
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http://dx.doi.org/10.1177/0956797619859340DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6794661PMC
August 2019

WITER: a powerful method for estimation of cancer-driver genes using a weighted iterative regression modelling background mutation counts.

Nucleic Acids Res 2019 09;47(16):e96

Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.

Genomic identification of driver mutations and genes in cancer cells are critical for precision medicine. Due to difficulty in modelling distribution of background mutation counts, existing statistical methods are often underpowered to discriminate cancer-driver genes from passenger genes. Here we propose a novel statistical approach, weighted iterative zero-truncated negative-binomial regression (WITER, http://grass.cgs.hku.hk/limx/witer or KGGSeq,http://grass.cgs.hku.hk/limx/kggseq/), to detect cancer-driver genes showing an excess of somatic mutations. By fitting the distribution of background mutation counts properly, this approach works well even in small or moderate samples. Compared to alternative methods, it detected more significant and cancer-consensus genes in most tested cancers. Applying this approach, we estimated 229 driver genes in 26 different types of cancers. In silico validation confirmed 78% of predicted genes as likely known drivers and many other genes as very likely new drivers for corresponding cancers. The technical advances of WITER enable the detection of driver genes in TCGA datasets as small as 30 subjects and rescue of more genes missed by alternative tools in moderate or small samples.
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http://dx.doi.org/10.1093/nar/gkz566DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6895256PMC
September 2019

The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study.

Lancet Psychiatry 2019 May 19;6(5):427-436. Epub 2019 Mar 19.

Department of Health Service and Population Research, Institute of Psychiatry, King's College London, London, UK.

Background: Cannabis use is associated with increased risk of later psychotic disorder but whether it affects incidence of the disorder remains unclear. We aimed to identify patterns of cannabis use with the strongest effect on odds of psychotic disorder across Europe and explore whether differences in such patterns contribute to variations in the incidence rates of psychotic disorder.

Methods: We included patients aged 18-64 years who presented to psychiatric services in 11 sites across Europe and Brazil with first-episode psychosis and recruited controls representative of the local populations. We applied adjusted logistic regression models to the data to estimate which patterns of cannabis use carried the highest odds for psychotic disorder. Using Europe-wide and national data on the expected concentration of Δ-tetrahydrocannabinol (THC) in the different types of cannabis available across the sites, we divided the types of cannabis used by participants into two categories: low potency (THC <10%) and high potency (THC ≥10%). Assuming causality, we calculated the population attributable fractions (PAFs) for the patterns of cannabis use associated with the highest odds of psychosis and the correlation between such patterns and the incidence rates for psychotic disorder across the study sites.

Findings: Between May 1, 2010, and April 1, 2015, we obtained data from 901 patients with first-episode psychosis across 11 sites and 1237 population controls from those same sites. Daily cannabis use was associated with increased odds of psychotic disorder compared with never users (adjusted odds ratio [OR] 3·2, 95% CI 2·2-4·1), increasing to nearly five-times increased odds for daily use of high-potency types of cannabis (4·8, 2·5-6·3). The PAFs calculated indicated that if high-potency cannabis were no longer available, 12·2% (95% CI 3·0-16·1) of cases of first-episode psychosis could be prevented across the 11 sites, rising to 30·3% (15·2-40·0) in London and 50·3% (27·4-66·0) in Amsterdam. The adjusted incident rates for psychotic disorder were positively correlated with the prevalence in controls across the 11 sites of use of high-potency cannabis (r = 0·7; p=0·0286) and daily use (r = 0·8; p=0·0109).

Interpretation: Differences in frequency of daily cannabis use and in use of high-potency cannabis contributed to the striking variation in the incidence of psychotic disorder across the 11 studied sites. Given the increasing availability of high-potency cannabis, this has important implications for public health.

Funding Source: Medical Research Council, the European Community's Seventh Framework Program grant, São Paulo Research Foundation, National Institute for Health Research (NIHR) Biomedical Research Centre (BRC) at South London and Maudsley NHS Foundation Trust and King's College London and the NIHR BRC at University College London, Wellcome Trust.
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http://dx.doi.org/10.1016/S2215-0366(19)30048-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7646282PMC
May 2019

Rational use of mesenchymal stem cells in the treatment of autism spectrum disorders.

World J Stem Cells 2019 Feb;11(2):55-72

Department of Psychiatry, the University of Hong Kong, Hong Kong, China.

Autism and autism spectrum disorders (ASD) refer to a range of conditions characterized by impaired social and communication skills and repetitive behaviors caused by different combinations of genetic and environmental influences. Although the pathophysiology underlying ASD is still unclear, recent evidence suggests that immune dysregulation and neuroinflammation play a role in the etiology of ASD. In particular, there is direct evidence supporting a role for maternal immune activation during prenatal life in neurodevelopmental conditions. Currently, the available options of behavioral therapies and pharmacological and supportive nutritional treatments in ASD are only symptomatic. Given the disturbing rise in the incidence of ASD, and the fact that there is no effective pharmacological therapy for ASD, there is an urgent need for new therapeutic options. Mesenchymal stem cells (MSCs) possess immunomodulatory properties that make them relevant to several diseases associated with inflammation and tissue damage. The paracrine regenerative mechanisms of MSCs are also suggested to be therapeutically beneficial for ASD. Thus the underlying pathology in ASD, including immune system dysregulation and inflammation, represent potential targets for MSC therapy. This review will focus on immune dysfunction in the pathogenesis of ASD and will further discuss the therapeutic potential for MSCs in mediating ASD-related immunological disorders.
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http://dx.doi.org/10.4252/wjsc.v11.i2.55DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6397804PMC
February 2019

High risk Epstein-Barr virus variants characterized by distinct polymorphisms in the EBER locus are strongly associated with nasopharyngeal carcinoma.

Int J Cancer 2019 06 7;144(12):3031-3042. Epub 2019 Jan 7.

Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong SAR, China.

Whether certain variants of Epstein-Barr virus (EBV) are linked to the pathogenesis of nasopharyngeal carcinoma (NPC), which shows a marked geographic restriction, remains an unresolved issue. We performed a case-control study comparing genomic sequences of EBV isolated from saliva samples of 142 population carriers with those from primary tumour biopsies derived from 62 patients with NPC of Hong Kong. Cluster analysis discovered five EBV subgroups 1A-C and 2A-B amongst the population carriers in contrast to the predominance of 1A and -B in the majority of NPC. Genome-wide association study (GWAS) identified a panel of NPC-associated single nucleotide polymorphisms (SNPs) and indels in the EBER locus. The most significant polymorphism, which can be found in 96.8% NPC cases and 40.1% population carriers of Hong Kong, is a four-base-deletion polymorphism downstream of EBER2 (EBER-del) from coordinates 7188-7191 (p = 1.91 × 10 ). In addition, the predicted secondary structure of EBER2 is altered with likely functional consequence in nearly all NPC cases. Using the SNPs and indels associated with NPC, genetic risk score is assigned for each EBV variant. EBV variants with high genetic risk score are found to be much more prevalent in Hong Kong Chinese than individuals of other geographic regions and in NPC than other EBV-associated cancers. We conclude that high risk EBV variants with polymorphisms in the EBER locus, designated as HKNPC-EBERvar, are strongly associated with NPC. Further investigation of the biological function and potential clinical application of these newly identified polymorphisms in NPC and other EBV-associated cancers is warranted.
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http://dx.doi.org/10.1002/ijc.32049DOI Listing
June 2019

Transdiagnostic dimensions of psychopathology at first episode psychosis: findings from the multinational EU-GEI study.

Psychol Med 2019 06 4;49(8):1378-1391. Epub 2018 Oct 4.

Division of Psychological Medicine and Clinical Neurosciences,MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University,Cardiff CF24 4HQ,UK.

Background: The value of the nosological distinction between non-affective and affective psychosis has frequently been challenged. We aimed to investigate the transdiagnostic dimensional structure and associated characteristics of psychopathology at First Episode Psychosis (FEP). Regardless of diagnostic categories, we expected that positive symptoms occurred more frequently in ethnic minority groups and in more densely populated environments, and that negative symptoms were associated with indices of neurodevelopmental impairment.

Method: This study included 2182 FEP individuals recruited across six countries, as part of the EUropean network of national schizophrenia networks studying Gene-Environment Interactions (EU-GEI) study. Symptom ratings were analysed using multidimensional item response modelling in Mplus to estimate five theory-based models of psychosis. We used multiple regression models to examine demographic and context factors associated with symptom dimensions.

Results: A bifactor model, composed of one general factor and five specific dimensions of positive, negative, disorganization, manic and depressive symptoms, best-represented associations among ratings of psychotic symptoms. Positive symptoms were more common in ethnic minority groups. Urbanicity was associated with a higher score on the general factor. Men presented with more negative and less depressive symptoms than women. Early age-at-first-contact with psychiatric services was associated with higher scores on negative, disorganized, and manic symptom dimensions.

Conclusions: Our results suggest that the bifactor model of psychopathology holds across diagnostic categories of non-affective and affective psychosis at FEP, and demographic and context determinants map onto general and specific symptom dimensions. These findings have implications for tailoring symptom-specific treatments and inform research into the mood-psychosis spectrum.
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http://dx.doi.org/10.1017/S0033291718002131DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6518388PMC
June 2019

HIV-1 Tat and methamphetamine co-induced oxidative cellular injury is mitigated by N-acetylcysteine amide (NACA) through rectifying mTOR signaling.

Toxicol Lett 2018 Dec 24;299:159-171. Epub 2018 Sep 24.

CUHK-SDU Joint Laboratory on Reproductive Genetics, School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China. Electronic address:

Methamphetamine (Meth) is an addictive psychostimulant whose abuse is intimately linked to increased risks for HIV-1 infection. Converging lines of evidence indicate that Meth also aggravates the symptoms of HIV-associated neurocognitive disorders (HAND), though the underlying mechanisms remain poorly understood. By using the lipophilic antioxidant N-acetylcysteine amide (NACA) as an interventional agent, we examined the roles of oxidative stress in autophagy and apoptosis induced by HIV-Tat (the transactivator of transcription), Meth or their combined treatment in human SH-SY5Y neuroblastoma cells and in the rat striatum. Oxidative stress was monitored in terms of the production of intracellular reactive oxygen species (ROS) and antioxidant reserves including glutathione peroxidase (GPx) and Cu,Zn-superoxide dismutase (SOD). NACA significantly reduced the level of ROS and restored GPx and SOD to levels comparable to that of normal control, implying a cytoprotective effect of NACA against oxidative stress elicited by Tat- and/or Meth. Protein expression of mammalian target of rapamycin (mTOR) was measured in SH-SY5Y cells and in the rat striatum to further explore the underlying mechanism of NACA protect against oxidative stress. The results support a beneficial effect of NACA in vivo and in vitro through rectification of the mTOR signaling pathway. Collectively, our study shows that NACA protects against Meth and/or Tat-induced cellular injury in vitro and in the rat striatum in vivo by attenuating oxidative stress, apoptosis and autophagy, at least in part, via modulation of mTOR signaling.
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http://dx.doi.org/10.1016/j.toxlet.2018.09.009DOI Listing
December 2018
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